In general, in a single crystal manufacturing apparatus based on the pulling CZ method, pressure in a highly pressure-proof airtight chamber is reduced to about 10 torr, and fresh argon (Ar) gas is sent into it. Polycrystals in a quartz crucible placed at the lower portion of the chamber are heated and molten, and seed crystal is immersed from above into the surface of the melt. Then, the seed crystal and the quartz crucible are rotated and moved up and down, and the seed crystal is pulled up. At the same time, a single crystal is grown, which comprises an upper cone portion in shape of a cone with its upper end protruding under the seed crystal and a lower cone portion in shape of a cone with a part of cylindrical body and the lower end protruded (the so-called ingot).
As the method to grow the crystal, Dash method is known. In this method, in order to eliminate dislocation (to turn to dislocation-free), which occurs on a seed crystal by thermal shock when the seed crystal is immersed into the surface of a melt, pulling rate is relatively quickened after immersing the seed crystal into the surface of the melt, and a portion with smaller diameter than the diameter of the seed crystal or a neck portion of 3-4 mm in diameter is formed, and then, the pulling operation of the upper cone portion is started.
Further, a single crystal with larger diameter and heavier weight (150-200 kg or more) cannot be pulled up via the neck portion with smaller diameter, and the following method has been proposed in the Japanese Patent Publication 5-65477, for example: After the neck portion with smaller diameter has been formed by Dash method, the pulling rate is relatively slowed down to form a portion with larger diameter. Then, the pulling rate is relatively quickened to form a portion with smaller diameter. Thus, "a spherical constricted portion" is formed, and by holding this constricted portion by a holder, a single crystal with larger diameter and heavier weight can be pulled up. As the conventional apparatus to hold the constricted portion, those disclosed in Japanese Patent Publications 7-103000 and 7-515 are known.
Also, a method to hold a part of the crystal body without forming the constricted portion as described above has been disclosed in Japanese Patent Publications Laid-Open 5-270974 and 7-172981. Further, Japanese Patent Publications Laid-Open 63-252991 and 5-270975 have proposed a method to form an "annular constricted portion" with diameter larger than that of the body portion between the upper cone portion and the body portion instead of the "spherical constricted portion" as described above and to hold this "annular constricted portion".
However, the single crystal pulling process is a process, which is very sensitive to vibration from outside and the crystal can be easily turned to polycrystal. Therefore, the problem in the pulling operation of the single crystal lies in that the crystal itself must be smoothly and gently moved from the necking position toward holding position such as the constricted portion without giving disturbances from outside. The holders as used in the past are mostly of squeezing type to squeeze the portion with larger diameter or straight body of the single crystal using two or more component members. In adopting such a structure, the squeezing force may be lost during trouble such as power suspension, and the single crystal may be dropped down. Further, because of high temperature inside the pulling furnace, holding mechanism must have heat-resistant property. Also, dust and particles generated from mechanical friction parts such as driving units must be removed as far as possible because these may adversely affect the single crystal. None of the conventional methods can perfectly solve all of these problems.